Segal resigned from the Senate effective June 15, 2014, prior to his upcoming appointment as Master of Massey College, Toronto for a seven-year term effective July 1, 2014.
Segal was inspired by a visit by Prime Minister John Diefenbaker to his Montreal High School the early 1960s. Segal is a graduate of the University of Ottawa. He was an aide to federal Progressive Conservative Leader of the Opposition Robert Stanfield in the early 1970s, while still a university student. At age 21, he was an unsuccessful candidate in Ottawa Centre for the Canadian House of Commons in the 1972 general election. He was defeated again in 1974.
As a member of the Big Blue Machine, Segal was a senior aide to Ontario Progressive Conservative Premier Bill Davis in the 1970s and 1980s and was named Deputy Minister at age 29. From 1992 to 1993 he was Chief of Staff to Prime Minister Brian Mulroney.
Segal finished second to Joe Clark after the first ballot of the 1998 Progressive Conservative leadership election, but chose to withdraw and support Clark (the eventual winner) in the second ballot runoff vote against third-place finisher David Orchard. He had also briefly considered running for the leadership in 1993.
Segal was summoned to the Senate of Canada in 2005 by the Governor General on the recommendation of Liberal Prime Minister Paul Martin.
He was the chairman of the Senate Foreign Affairs Committee until he "reluctantly" agreed to resign on the request of the government, which reportedly wished to appoint a more ideologically conservative Senator to the role after the committee issued a report critical of the Conservative government's foreign aid policy. Segal insisted, however, that the move was an administrative one. Segal later served as Chair of the Special Senate Committee on Anti-Terrorism.
In December 2013, he announced his intention to resign from the Senate in June 2014, twelve years before he reaches the mandatory retirement age of 75, to accept an academic appointment as Master of Massey College, Toronto.
On July 7, 2010, he was appointed to the Commonwealth Eminent Persons Group (EPG) by Secretary General Kamalesh Sharma. The group's mandate is to set out decisive recommendations on how to strengthen the Commonwealth and fulfill its potential in the 21st century. In December 2011 the federal government appointed him special envoy to the Commonwealth with the task of convincing individual countries to sign on to the EPG's 106 recommendations.
Segal espouses a moderate brand of conservatism that has little in common with British Thatcherism or US neoconservatism. He is a Red Tory in the tradition of Benjamin Disraeli, Sir John A. Macdonald, John George Diefenbaker and his mentors Robert Stanfield and Bill Davis. This political philosophy stresses the common good and promotes social harmony between classes. It is often associated with One Nation Conservatism. The focus is on order, good government and mutual responsibility. Individual rights and personal freedom are not considered absolute. In his book Beyond Greed: A Traditional Conservative Confronts Neo-Conservative Excess (Toronto: Stoddart, 1997), Segal sought to distinguish what he called “traditional” conservatives from neo-conservatives, notably those in the United States.
In an earlier book, his 1996 memoir No Surrender (page 225), Segal wrote: "Progressive Conservatives cannot embrace the nihilistic defeatism that masquerades as a neo-conservative polemic in support of individual freedom and disengagement." He went on to deplore "American fast-food conservatism." In a speech to the National Press Club on June 21, 1995, Segal referred to the "selfish and directionless nature of the American revolution -- which was more about self-interest, mercantile opportunity, and who collected what tax than it was about tolerance or freedom."
Segal opposed on civil liberties grounds the imposition of the War Measures Act by Prime Minister Pierre Trudeau in the October Crisis of 1970. He favours strengthening Canada's military and encouraging investment, while maintaining a strong social safety net. His 1998 proposal to reduce Canada's Goods and Services Tax from 7% to 6% (and then 5%) was adopted by Stephen Harper and the Conservative Party in 2005. During his leadership campaign he stated his support for capital punishment. Segal's most recent book is The Long Road Back: The Conservative Journey, 1993-2006 (Toronto: HarperCollins, 2006).
On 6 June 2012, Segal had a comment published in the National Post outlining his views on Basic Income. In December 2012, Segal published an essay in the Literary Review of Canada promoting the benefits of a guaranteed annual income.
In the 1980s and 1990s, Segal became a television pundit and newspaper columnist. In the private sector, Segal has been an executive in the advertising, brewing, and financial services industries.
Segal's book Two Freedoms: Canada's Global Future was published by Dundurn Press in April 2016.
Segal lives in Kingston, Ontario, and until 2014 was a faculty member at Queen's University's School of Policy Studies, and has also taught at the university's school of business. He served as president of the Institute for Research on Public Policy, a Montreal think tank, from 1999 to 2006. He sits on the board of directors and is a distinguished fellow at the Canadian Defence and Foreign Affairs Institute. He is also a member of the Trilateral Commission.
Segal was appointed Master of Massey College in the University of Toronto effective at the end of June 2014 and retired from the Senate in order to accept the position.
In 2003, Segal was made a Member of the Order of Canada which was later promoted to the grade of Officer. Segal holds an honorary doctorate degrees from the Royal Military College of Canada and the University of Ottawa.
Hugh Segal was named honorary captain in the Royal Canadian Navy in 2004. 
He was made chair of the NATO Association of Canada in 2013.
In 2016, he was made a member of the Order of Ontario.
He is the brother of corporate executive and former university administrator Brian Segal and artist Seymour Segal. He is married to Donna Armstrong Segal, a former Ontario Ministry of Health executive. They have one daughter, Jacqueline.How Canadian conservatism differs from the American version Online video conference by Hugh Segal, part of the larger Predominance in the U.S. : A Moment or an Era ? 21 experts from the U.S. and abroad, including former Bush speechwriter David Frum, ponder the future of conservatism.